Disconnectable joint busbars are commonly used in electrical power transmission networks in urban environments. The busbar includes a body with two or more posts or lugs extending therefrom and an electrical insulation layer covering the body. Electrical power cables to be spliced are provided with a cable termination lug or connector. Each cable termination lug is disconnectably and reconnectably secured to a respective busbar lug by a bolt or the like, for example.
Disconnectable joint assemblies as described above are useful in urban network applications where a utility may need the ability to disconnect a joint to sectionalize a piece of cable for repair, for example. By way of example, a bad or damaged cable may be disconnected from the busbar to remove the cable from the circuit in a quick and efficient manner, and then reconnected to the busbar after the repair is made.
In order to protect the joint, cable, busbar and cable terminal lug from the environment (e.g., moisture) and to protect technicians from the electrically energized components, joint sleeve systems are employed. Typically, the joint sleeve system includes a relatively stiff push-on joint sleeve formed of EPDM rubber and a plurality of push-on cable adapters having a given outer diameter and different inner diameters. The joint sleeve has an effectively fixed inner diameter and a cable adapter of appropriate outer diameter is selected to build up the outer diameter of the cable to suitably fit the inner diameter of the joint sleeve. The cable adapter is forcibly pushed onto the cable and the joint sleeve is forcibly pushed onto the cable adapter and the busbar to span the joint and overlap the insulation layers of the cable and the busbar.
Disconnectable joint sleeve systems as described can suffer several significant drawbacks. Because the push-on cable adapters each have a limited cable diameter use range, multiple different sizes of cable adapters are required to cover many intended use ranges. The cable adapters may be difficult to push on and may require holding collars to prevent them from sliding out of position when the joint sleeve is pushed over them. The completed joint sleeve assembly may be long and bulky, a particular drawback when used in congested urban manholes, for example. Because the joint assembly is relatively still, it may lose its seal with the cable adapter or the busbar when the cables are bent or moved.